全文获取类型
收费全文 | 9722篇 |
免费 | 826篇 |
国内免费 | 419篇 |
专业分类
耳鼻咽喉 | 91篇 |
儿科学 | 110篇 |
妇产科学 | 219篇 |
基础医学 | 1795篇 |
口腔科学 | 297篇 |
临床医学 | 692篇 |
内科学 | 1111篇 |
皮肤病学 | 276篇 |
神经病学 | 222篇 |
特种医学 | 193篇 |
外国民族医学 | 1篇 |
外科学 | 760篇 |
综合类 | 1793篇 |
现状与发展 | 1篇 |
预防医学 | 742篇 |
眼科学 | 56篇 |
药学 | 741篇 |
5篇 | |
中国医学 | 266篇 |
肿瘤学 | 1596篇 |
出版年
2024年 | 20篇 |
2023年 | 110篇 |
2022年 | 268篇 |
2021年 | 322篇 |
2020年 | 303篇 |
2019年 | 343篇 |
2018年 | 285篇 |
2017年 | 301篇 |
2016年 | 284篇 |
2015年 | 327篇 |
2014年 | 517篇 |
2013年 | 502篇 |
2012年 | 482篇 |
2011年 | 666篇 |
2010年 | 527篇 |
2009年 | 527篇 |
2008年 | 544篇 |
2007年 | 587篇 |
2006年 | 545篇 |
2005年 | 426篇 |
2004年 | 414篇 |
2003年 | 394篇 |
2002年 | 344篇 |
2001年 | 345篇 |
2000年 | 350篇 |
1999年 | 274篇 |
1998年 | 160篇 |
1997年 | 133篇 |
1996年 | 81篇 |
1995年 | 68篇 |
1994年 | 53篇 |
1993年 | 35篇 |
1992年 | 45篇 |
1991年 | 18篇 |
1990年 | 26篇 |
1989年 | 24篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 32篇 |
1984年 | 39篇 |
1983年 | 18篇 |
1982年 | 35篇 |
1981年 | 28篇 |
1980年 | 22篇 |
1979年 | 16篇 |
1978年 | 16篇 |
1976年 | 12篇 |
1975年 | 13篇 |
1974年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Gérald Vanzetto Marc Janier Daniel Fagret Luc Cinotti Xavier André-Fouet Michel Comet Jacques Machecourt 《European journal of nuclear medicine and molecular imaging》1997,24(2):170-178
The best test presently available to ascertain residual viability within an infarct-related area involves the use of fluorine-18
fluorodeoxyglucose (FDG) to detect the persistence of some cellular metabolism. Rest reinjection of thallium-201 is a less
accurate alternative but is easy to perform. Iodinated fatty acids, which are used with standard gamma cameras, are proposed
as markers of cellular metabolism. This study was performed to assess the value of 16-iodo-3-methyl-hexadecanoic acid (MIHA)
as a marker of the residual cellular metabolism by comparison with FDG in patients with a recent myocardial infarction, and
to evaluate its contribution compared with the201Tl stress-redistribution-reinjection technique. Stress-redistribution-reinjection201T1 imaging, rest MIHA imaging and glucoseloaded FDG imaging were performed in 22 patients with recent myocardial infarction.
Out of the 628 myocardial segments obtained from the left ventricular analysis, 400 were hypoperfused (relative uptake <0.75
of maximum uptake on stress201T1 imaging), 177 of which were severely hypoperfused (relative uptake <0.50). Receiver operating characteristic (ROC) curves
for predicting metabolic myocardial viability with FDG were derived from the results in respect of (a)201T1 activity during exercise, redistribution and reinjection and (b) MIHA up-take, using the two FDG thresholds most commonly
considered to define metabolic viability (0.50 and 0.60). Analysis of the 400 hypoperfused segments demonstrated that201T1 reinjection was the most accurate test in predicting the presence of myocardial viability (area under the ROI curves=0.85
and 0.86 at the 0.50 and 0.60 FDG thresholds, respectively;P<0.05 vs other tests). The global predictive values of MIHA and201T1 reinjection were, respectively, 0.87 and 0.89 at the 0.50 FDG threshold (NS), and 0.82 and 0.87 at the 0.60 FDG threshold
(NS). When only the 177 severely hypoperfused segments were considered,201T1 reinjection remained the most accurate test (accuracy 0.84 at the 0.50 FDG threshold and 0.82 at the 0.60 FDG threshold),
while the accuracy of MIHA decreased significantly (0.78 at the 0.50 FDG threshold and 0.73 at the 0.60 FDG threshold,P<0.05 vs201T1 reinjection). In all circumstances, MIHA was less specific than201T1 reinjection for the detection of metabolic viability. In conclusion, in patients with recent myocardial infarction, MIHA
accurately detects the persistence of metabolic viability, but is not superior to201T1. 相似文献
3.
Danuta Wasserman Christer HellstrÖm Jerzy Wasserman Olof Beck Eva Andersson Marie Åsberg 《Archives of Suicide Research》1997,3(3):153-169
The aim of this study was to investigate markers of serotonin and immune function in suicidal patients. Cytotoxic activity of natural killer cells (NK) and CD16 lymphocytes were studied in 28 suicide attempters and 26 healthy controls, and related in patients to 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF). Patients with CSF 5-HIAA below the median had significantly lower NK cell activity than other patients. CD16 cell frequency was significantly lower in patients than in controls, and patients also tended to have lower NK cell cytotoxicity than healthy controls. There were no statistically significant correlations between 4-hydroxy-3methoxyphenyl glycol (HMPG), homovanillic acid (HVA), CSF cortisol and NK cell activity. The results support the hypothesis of compromised immune function in suicidal patients with evidence of disordered serotonin function. 相似文献
4.
Helene Z. Hill Maimu Ohanian George J. Hill Richard Winne 《Journal of surgical oncology》1987,34(4):264-267
Intraoperative radiation therapy (IORT) research is limited by the lack of small-animal models. We have implanted B16 melanoma into mouse kidneys, which we subsequently operated upon and irradiated with beta rays from a 90Sr ophthalmic applicator. The IORT has effectively prolonged survival and produced some cures. The strategy should be applicable to other murine tumors and to other internal implantation sites. 相似文献
5.
目的 将人乳头瘤病毒16型(Human papillomavirus type 16,HPV-16)的晚期表达蛋白E7上的抗原24肽(从第38位氨基酸到第61位氨基6病毒感染防治酸)与人免疫球蛋白G的重链恒定区融合表达,并以此融合蛋白作为抗原,可能为HPV-1提供免疫治疗方法。方法 利用PCR方法分别扩增HPV-16 E7(38-61)24肽的DNA片段和人免疫球蛋白G的重链恒定区DNA片段,并构建到pEV21a表达载体上,转化入E.coli中表达,利用SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)和蛋白质免疫印迹(Western-blotting)的方法对表达结果进行鉴定。结果 构建的表达载体HPV16E7e/hIgGHCCR-pET21a经酶切鉴定和测序显示序列正确;通过SDS-PAGE和Western-blotting的鉴定,重组融合蛋白Mr约40000,表达量可占菌体蛋白的20%左右。结论 成功构建HPV16-E7的抗原多肽片段和人免疫球蛋白G的重链恒定区的融合蛋白,并可在E.coli中高效表达。 相似文献
6.
给出了用“混合型”雅可比级数的泰勒平均逼近黎普希兹函数类的点态估计。 相似文献
7.
桂永浩 《中国超声医学杂志》1995,(12)
对20个16三体染色体异常小鼠胚胎进行了多普勒超声心动图研究。胎龄从10天至15天。9例发现流入道返流波型,6例发现流出道返流波型。120例染色体正常胚胎无一例发现返流波型。16三体小鼠模型作为先天性心脏病研究的理想模型,本文首次提供了对此类模型胚胎血液动力学研究的非创伤性监测方法。 相似文献
8.
Gregory E Demas Randy J Nelson Bruce K Krueger Paul J Yarowsky 《Behavioural brain research》1998,90(2):199-201
To evaluate the cognitive phenotype of the segmental trisomy 16 (Ts65Dn) mouse, a model of Down Syndrome (DS, trisomy 21), we assessed spatial working and reference memory using a 12-arm radial maze (RAM). Ts65Dn mice made a greater number of reference memory errors across trials compared to control mice. Both genotypes showed improvement across trials, although improvement was slower in Ts65Dn mice. Ts65Dn mice also made a greater number of working memory errors on the RAM, and in contrast to control mice, did not improve across trials, always performing at near-chance levels. These results provide evidence for both spatial working and reference memory deficits in Ts65Dn mice, characteristics of cognitive dysfunction. 相似文献
9.
Abnormality of chromosome 16 and its phenotypic expression 总被引:2,自引:0,他引:2
An abnormality of chromosome 16 in which there is extra genetic material present on the short arm (46, XY, 16p+) has been identified. This chromosomal aberration was associated with multiple congenital anomalies, including mid-facial hypoplasia, arthrogryposis, and mental retardation. On the basis of the cytogenetic appearance and the phenotype of the patient, this may represent a partial 16 trisomy. Unlike most abnormalities of chromosome 16, this syndrome was compatible with life. 相似文献
10.
Townes-Brocks syndrome (TBS) is an autosomal dominant disorder with multiple malformations and variable expression. Major findings include external ear anomalies, hearing loss, preaxial polydactyly and triphalangeal thumbs, imperforate anus, and renal malformations. Most patients with Townes-Brocks syndrome have normal intelligence, although mental retardation has been noted in a few. 相似文献